Hello friends I have a Yamaha htr5280 amplifier turns on and off. Sometimes once and sometimes lasts longer. I am technician with a lot of experience in sound equipment but this problem I could not solve. Please request your colaboracion.gracias.

I have already exhausted all my recurdos voltages are correct in the source. I have changed some capacitors but I have not been successful. The problem is that I'm not sure where the fault is. This happens to all yamaha. It seems to me that they are made with a limit of life because everything is well and suddenly that problem appears. If someone solved it I would like to see it.Thank you